Polycythaemia

Question 1

what is it?

Answer 1

abnormally increased concentration of Hb in the blood

either through reduction of plasma volume or increase in red cell numbers

Question 2

erythropoietin

Answer 2

hormone secreted by kidneys that increases the rate of production of RBCs in response to falling levels of O2 in the tissues

Question 3

PCV

Answer 3

packed cell volume
aka hematocrit

measure of viscosity/thickness of the blood

related to the level of Hb

Question 4

aetiology of relative polycythaemia

RBC vol normal, but decrease in plasma vol

Answer 4

acute - alcohol/dehydration

chronic - obesity/HT/high alcohol/tobacco intake

Question 5

aetiology of absolute polycythaemia

true increase in red cell vol

Answer 5

primary- polycythaemia rubra vera

secondary- from an appropriate (e.g. due to hypoxia -altitude) /inappropriate increase in EPO

Question 6

how is polychythaemia defined?

Answer 6

an increase in Hb, PCV and erythrocyte count

Question 7

Polycythaemia rubra vera: PRV

Answer 7

malignant proliferation of a clone derived from 1 pluripotent marrow stem cell

mutation in JAK2 gene

erythroid progenitor offspring don’t need EPO to avoid apoptosis

excess proliferation of RBCs, WBCs and platelets

Question 8

Clinical presentation of PRV

Answer 8

insidious, easily missed

• incidental finding of high Hb or Sx of hyper viscosity

headaches, dizziness, tinnitus, visual disturbance

Question 9

Dx

Answer 9

Major criteria: Hb above a certain range

Minor criteria:

• BM biopsy- hypercellularity for age
• Serum EPO below normal

Question 10

Management
+
complications

Answer 10

goal: HTC less than 0.45
venesection
hydroxycarbamide to reduce platelet count
low dose aspirin

transition to acute leukaemia in ~5%

transition to myelofibrosis in 30%

Question 11

Mx THIS CARD IS NOT LETTING ME CHANGE IT ARGHGHG :@

Answer 11

aim: HTC